1. Field of the Invention
The present invention relates to an air compression device assembled in an air compressor, and more particularly to an air compression device capable of adjusting an air chamber capacity to change air input and air output.
2. Related Art
An air compression device is generally assembled in an air compressor, so as to compress and then exhaust the air inhaled by the air compressor. FIG. 1 illustrates a conventional air compression device. Referring to FIG. 1, an air chamber 101 is formed in the air compression device 10, a first rotor 1011 and a second rotor 1012 are assembled in the air chamber 101, and the air chamber 101 is in communication with an air inlet 102 and an air outlet (not shown). When the air enters the air chamber 101 through the air inlet 102, the first rotor 1011 and the second rotor 1012 are driven to rotate at the same time. When the two rotors (1011, 1012) rotate, the air is compressed to generate compression air, and then the compression air is exhausted through the air outlet. Through the above operation, a process of air admission, compression, and exhaust is successively completed. In the conventional air compression device 10, the air chamber 101 is fixed in capacity, and generates fixed air output and fixed power accordingly. When a user needs to increase the air output to generate higher power due to a power demand, the air output generated by the air compression device 10 is increased by adjusting an air compression rate of the first rotor 1011 and the second rotor 1012. Through such operation, the air output may be increased to improve the power output, but the more the air output improves, the more motor power the two rotors (1011, 1012) consume. In addition, when the required power output is smaller than the minimum power provided by the air compression device 10, energy waste is caused. Moreover, when the two rotors (1011, 1012) operate, the rate has a limit value, and when the required power output is greater than the rated power provided by the air compression device 10, insufficient air output is caused, and the power cannot be improved. If the above air compression device 10 is applied to an air intake system of a vehicle engine, the required air output of a car apparently and greatly differs from that of a moped. However, in order to achieve various demands on the air output, many groups of the air compression devices 10 need to be used in coordination, which causes rather high limitation for the application of the compression air, and does not conform to the consideration on the manufacturing cost.